Method for producing a vehicle composite component

ABSTRACT

A method for producing a vehicle composite component with a layer structure having a core layer in a molding tool, the core layer being formed with regions of different thickness is provided. Steps for this method may include placing a cover layer, in particular a preformed cover layer, which in particular forms an outer skin of the vehicle composite component, onto a mold base plate of the open molding tool; introducing a first fiber layer, which is impregnated with PU resin and has not been subjected to forming, between the cover layer and a first mold counterplate of the open molding tool; closing the molding tool and compression molding the first fiber layer, which is impregnated with PU resin, against the cover layer, as a result of which a preform with a first support layer containing the first fiber layer is formed and hardened while supplying heat.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from European Patent Application NumberEP 20191663.2, filed Aug. 19, 2020, which is hereby incorporated hereinby reference in its entirety for all purposes.

FIELD

The invention relates to a method for producing a vehicle compositecomponent with a layer structure having a core layer in a molding tool,the core layer being formed with regions of different thickness.

Such a vehicle composite component is e.g. an outer surface part of aroof module or a trim component of a vehicle or else a cover of a roofopening system, such as a sliding roof or a spoiler roof, a roofelement, e.g. of a hardtop convertible, or a luggage compartment loadingfloor.

BACKGROUND

DE 10 2012 013 538 B4 has disclosed a vehicle sandwich element which isproduced by a method in which foamable material is injected between twocover layers. The two cover layers are kept at a distance from oneanother on opposite tool surfaces in a tool by means of a holdingdevice, with the result that the foamable material can be injected intoa free space between the two cover layers. The cover layers, which arepreferably in the form of dry semifinished fibrous products, are thusfixed to the tool surfaces during the foaming operation and do notchange position while being penetrated by foamable material andimpregnated in the process and at the same time are fixedly connected tothe foamed and hardened core of the sandwich element. Holding devicesproposed are suction devices, devices which act with a magnetic force,mechanical holding devices with hooks or the like, or adhesive means.

SUMMARY

The invention is based on the object of specifying a method mentioned atthe outset that is improved in terms of the production of a vehiclecomposite component having regions with considerably different componentthicknesses over its surface extent.

This object is achieved in the case of the method mentioned at theoutset by the steps mentioned below:

1.1 placing a cover layer, in particular a preformed cover layer, whichin particular forms an outer skin of the vehicle composite component,onto a mold base plate of the open molding tool,1.2 introducing a first fiber layer, which is impregnated with PU resinand has not been subjected to forming, between the cover layer and afirst mold counterplate of the open molding tool,1.3 closing the molding tool and compression molding the first fiberlayer, which is impregnated with PU resin, against the cover layer, as aresult of which a preform with a first support layer containing thefirst fiber layer is formed and hardened while supplying heat,1.4 opening the molding tool and replacing the first mold counterplatewith a second mold counterplate with a highly structured mold surface,1.5 introducing a second fiber layer, which is impregnated with PU resinand has not been subjected to forming, between the preform arranged onthe mold base plate and the second mold counterplate of the open moldingtool,1.6 closing the molding tool and injecting foamable PU between the firstsupport layer of the preform and the second fiber layer, the PU foamforming the core layer pressing the second fiber layer against thesecond mold counterplate, which has a profiled mold surface, and shapingit thereon as a second profiled support layer,1.7 opening the molding tool and removing the composite componentformed.

Advantageous configurations of the invention are specified in thedependent claims.

In the case of the method according to the invention, the mold baseplate is attached e.g. to a lower part of the molding tool and the moldcounterplate is attached to a tool upper part. The opening and closingmovement of the molding tool is expediently effected by a verticalmovement of the tool upper part, which supports the mold counterplate.However, the molding tool may also have a left tool half and a righttool half, for example, which move the mold base plate and the moldcounterplate toward one another in a horizontal opening and closingmovement.

The first mold counterplate has a mold surface for shaping the inner orrear side of the preform. The preform contains the first support layerwith the external cover layer, e.g. a thermoformed film which is basedon a plurality of plastic layers, for example, or a coatable SMC shell.

The first support layer is formed by a first fiber layer, which issprayed on one side or on both sides with polyurethane resin outside themolding tool by means of a spray head or the like. The first fiber layeris e.g. a loose layered arrangement of reinforcing fibers, such as glassfibers or a fiber mat or glass-fiber mat in the form of a bare plywithout special three-dimensional forming, such that as a result noprefabricated shaping of the composite component is effected. The wetfirst fiber layer, which is impregnated with PU resin in this way andhas not been subjected to forming, is placed into the open molding toolonto the cover layer.

The second mold counterplate molds the inner side of the compositecomponent. For this purpose, the second mold counterplate has such ahighly structured mold surface, and one which is three-dimensionallyformed in such a way, that it makes it possible to produce regions ofthe composite component, such as e.g. raised component borders aroundthe periphery or reinforcing ribs or the like, with a considerablygreater component thickness than planar portions of the compositecomponent formed with a lower thickness. In this respect, the secondsupport layer, which has a highly contoured shape, is formed on thesecond mold counterplate by means of the second fiber layer.

The second fiber layer is impregnated with PU resin in a mannercorresponding to the first fiber layer and is not subjected to forming,and in particular still wet with PU resin is introduced between thepreform arranged on the mold base plate and the second mold counterplateof the open molding tool.

When, in the method sequence, the molding tool is closed and foamable PUis injected between the first support layer of the preform and thesecond fiber layer, the still-formable second fiber layer is pressedagainst the highly profiled or highly structured mold surface of thesecond mold counterplate and shaped thereon by the PU foam forming thecore layer as the second profiled support layer and hardened whilesupplying heat.

The method according to the invention thus does not require anypreformed second or inner fiber layer or any preformed second or innersupport layer which predefine the shape of the composite component. Bycontrast, in the case of the method according to the invention, theforming of the second or inner support layer is performed in the moldingtool and the component shape is created in this way.

Moreover, an extensive design freedom regarding the shape of thecomposite component is a significant advantage, since thethree-dimensional design of the composite component is subject tovirtually no limitation. Furthermore, the positional accuracy can beimplemented with greater tolerances during the method sequence, e.g.during the operations of handling and positioning in the molding tool.The method steps are considerably reduced in comparison with methodswith preformed cores, such as e.g. honeycomb or foam structures. Theinterior surface does not have any colored imprint or irregularities,and therefore no additional lamination of the inner surface isnecessary.

In the case of the method, it is particularly preferred if the firstsupport layer and the second support layer are pressed together at theedge and adhesively bonded with PU and enclose the core layer. In thisway, for example, a solid and stiff flange can be formed at the edge orperiphery of the composite component. As a result, the compositecomponent is sealed and the narrow flange is matched to an imbricativearrangement of the composite component on the vehicle, thus forming ageometric transition to attachment parts and terminating with the sealof the vehicle.

Expediently, the first fiber layer and/or the second fiber layer are/isimpregnated outside the molding tool by spraying PU resin on one side oron both sides.

According to a preferred method configuration, it is provided thatunordered or ordered fibers or at least one fiber mat form/forms thefirst fiber layer or fiber ply and/or the second fiber layer or fiberply, and that the fibers are in particular glass fibers. However, it isalso possible in principle to use other reinforcing fibers, such asnatural fibers or carbon fibers.

Furthermore, it may be provided that a spacer is applied to the preformarranged on the mold base plate and then the second fiber layer isintroduced between the spacer and the second mold counterplate. Duringthe subsequent closing of the molding tool, the spacer keeps the secondfiber layer at a distance from the preform and in contact with thesecond mold counterplate. This provides the space into which foamable PUplastic is injected to produce the core layer of the compositecomponent. The spacer remains in the core layer or in the PU foam.

The spacer is for example a self-inflatable film or athree-dimensionally deformable mat structure, e.g. composed of a plasticsuch as polyester.

BRIEF DESCRIPTIONS OF THE DRAWINGS

A method according to the invention for producing a vehicle compositecomponent will be explained in more detail below with reference to thedrawing, in which:

FIG. 1 shows, in schematic illustrations 1.1 to 1.9, a molding tool in aplurality of positions when carrying out a method for producing avehicle composite component;

FIG. 2 shows, in schematic illustrations 2.1 to 2.9, the molding tool ina plurality of positions when carrying out a variant of the method forproducing the vehicle composite component;

FIG. 3 shows, in schematic illustrations 3.1 to 3.9, the molding tool ina plurality of positions when carrying out another variant of the methodfor producing the vehicle composite component; and

FIG. 4 shows, in a sectional view in a schematic illustration, a vehiclecomposite component produced according to the method.

DETAILED DESCRIPTION

A vehicle composite component 1 (see FIG. 4) which forms, e.g., avehicle outer surface component or a cover of a roof module, has asandwich-like layer structure 2 with a polyurethane foam core or PU foamcore as core layer 3. The core layer 3 is covered on one side by a firstsupport layer 4 and on the other side by a second support layer 5. Anouter cover layer 6 is located on the first support layer 4.

The first support layer 4 together with the cover layer 6 and the secondsupport layer 5 form an edge region 7 of the component 1, the end ofwhich is e.g. in the form of an in particular web-like flange 8. An edgeportion 9 of the first support layer 4 and an edge portion 10 of thesecond support layer 5 are directly connected to one another at the edgeregion 7 and in particular at the web-like flange 8. The component 1accordingly does not contain any core layer 3 in its edge region 7 or inthe flange 8.

The first support layer 4 and the second support layer 5 are formed fromfiber plies or fiber layers provided with PU resin. The fiber plies areformed e.g. from glass fibers and are in particular glass-fiber matswhich have been wetted or impregnated as a result of being sprayed onone side or on both sides with PU resin before having been hardened assupport layers in a molding tool under pressure and while supplyingheat.

The cover layer 6 in particular forms an outer skin or outer side of thevehicle composite component 1.

The core layer 3 consists of a PU foam, which has been foamed in themolding tool from an injected PU plastic.

A method for producing a vehicle composite component 1 according to theinvention will be explained below.

A molding tool 11 (see FIG. 1.1) has a mold base plate 12 and a moldcounterplate 13 which form a mold cavity 14 when the molding tool 11 isclosed. The mold base plate 12 is attached e.g. to a lower tool half ofthe molding tool 11 and the mold counterplate 13 is attached to theoppositely situated upper tool half.

When the molding tool 11 is open, the cover layer 6 comes to lie againstthe mold base plate 12 or is placed onto the mold base plate 12. Thecover layer 6, which preferably forms an outer side or outer skin of thein particular planar vehicle composite component 1, is expedientlypreformed and matched to a shaping mold surface of the mold base plate12. The cover layer 6 is e.g. a thermoformed film which is based on aplurality of plastic layers, for example, or a coatable SMC shell. Themold base plate 12 may have a negative-pressure device 15 which containse.g. at least one suction channel, with the result that the cover layer6 can be held by suction against the mold base plate 12 owing tonegative pressure.

Outside the molding tool 11 (FIG. 1.2), a first fiber layer 16 issprayed on one side or on both sides with polyurethane resin by means ofa spray head 17 or the like. The first fiber layer 16 is e.g. a looselayered arrangement of reinforcing fibers, such as glass fibers or afiber mat or glass-fiber mat in the form of a bare ply without specialthree-dimensional forming, such that as a result no shaping of thecomponent is effected. The first fiber layer 16, which is impregnatedwith PU resin in this way and has not been subjected to forming, isintroduced into the open molding tool 11 (FIG. 1.3) and placed onto thecover layer 6, which is arranged on the mold base plate 12. The moldbase plate 12 is preheated by means of a heating device 18 having e.g.heating channels arranged in the mold base plate 12.

Subsequently, the molding tool 11 is closed (FIG. 1.4) in that the twotool halves move the mold base plate 12 and the mold counterplate 13against one another. In the process, while supplying heat, the firstfiber layer 16, which is impregnated with PU resin, iscompression-molded against the cover layer 6 into a layer-likecomposite, which forms a preform 19. The preform 19 contains the firstsupport layer 4, which is formed by the first fiber layer 16, which isimpregnated with the PU resin, and hardened while supplying heat. The PUresin of the first fiber layer 16 thus produces the intimate bond withthe cover layer 6.

According to a first method alternative, after opening the molding tool11 (FIG. 1.5), the preform 19 formed while supplying heat and underpressure is removed from the molding tool 11 or from the mold base plate12 and inserted into a molding tool 11 (FIG. 1.6), which has anidentical mold base plate 12 but has a second mold counterplate 13′,which has a mold surface formed differently to that of the first moldcounterplate 13, instead of the first mold counterplate 13, the moldsurface of which is matched to the form of the cover layer 6.

According to a second method alternative, the preform 19 formed remainson the mold base plate 12 of the molding tool 11 after opening themolding tool 11, but the upper first mold counterplate 13 is replaced bya second mold counterplate 13′ with a differently formed mold surface.

The upper second mold counterplate 13′ has a mold surface which has astructured form such that the mold cavity 14 has a plurality of regionsin which the spacings between the lower mold base plate 12 and/orbetween the inner surface of the preform 19 arranged thereon and themold surface of the upper second mold counterplate 13′ are considerablydifferent. The composite component 1 is accordingly produced withregions of considerably different component thicknesses.

Produced outside the molding tool 11 is a second fiber layer 20, whichis formed in the same way as the first fiber layer 16 (FIG. 1.7). Thesecond fiber layer 20, which likewise is not specially preformed and isimpregnated with PU resin, is introduced into the open molding tool 11(FIG. 1.8) and placed on the preform 19, an edge portion of the secondfiber layer 20 being in contact with an edge portion of the preform 19.

The molding tool 11 is closed (FIG. 1.9), the mold counterplate 13′ andthe mold base plate 12 pressing the edge portions of the second fiberlayer 20 and of the preform 19 that lie on top of one another againstone another. A foamable PU plastic is injected between the hardenedfirst support layer 4 of the preform 19 and the still-formable secondfiber layer 20, which is impregnated with PU. The pressure during theinjection of the PU plastic and during the foaming of the PU foampresses the second fiber layer 20 against the second mold counterplate13′, which has a profiled mold surface, and shapes it thereon as asecond profiled support layer 5. The PU foam forms the core layer 3 ofthe composite component 1 and is completely enclosed by the two supportlayers 4 and 5. The structured profiled mold surface of the second moldcounterplate 13′ makes it possible to produce composite componentshaving large differences in thickness in different component regions,the core layer 3 forming the corresponding mold as a result of thefoaming and not requiring any mechanical finishing, such as cutting ormilling, of the foam in the process.

While supplying heat, the composite component 1 is hardened in theclosed molding tool 11. The molding tool 11 is then opened and thecomposite component 1 formed is removed.

The edge region 7 of the composite component 1 ends in the in particularweb-like flange 8 (see FIG. 4). The edge portion 9 of the first supportlayer 4 and the edge portion 10 of the second support layer 5 aredirectly connected to one another at the edge region 7.

The method described above can be carried out with alternative methodsteps (see FIG. 2). The first method steps, illustrated in FIGS. 2.1 to2.5, correspond to method steps 1.1 to 1.5 described above. Afterremoving the preform 19 from the molding tool 11 or from the mold baseplate 12 (FIG. 2.5), the molding tool 11 is modified or exchanged insuch a way that the second mold counterplate 13′ is arranged on thelower tool half of the molding tool 11 and the mold base plate 12 isarranged on the upper tool half (FIG. 2.6). The preform 19 is insertedinto the open molding tool 11 and held by suction against the mold baseplate 12 by means of the negative-pressure device 15.

As an alternative to this, the preform 19 formed remains in the closedmolding tool 11 or, after the molding tool 11 is opened, on the moldbase plate 12 of the molding tool 11, and when the molding tool 11 isbeing changed is furthermore held on the mold base plate 12, inparticular by suction by means of an active negative-pressure device 15.

Furthermore (see FIG. 2.7, correspondingly FIG. 1.7), the secondimpregnated fiber layer 20 is produced outside the molding tool 11 andintroduced into the open molding tool 11 (2.8) in which the preform 19is held owing to negative pressure on the mold base plate 12 arranged onthe upper tool half. When the molding tool 11 is being closed (FIG. 2.8a), the edge portions of the preform 19 and of the second fiber layer 20are pressed against one another, while the preform 19 is furthermoreheld on the mold base plate 12 arranged at the top by means of negativepressure.

The injecting of the foamable PU plastic between the hardened firstsupport layer 4 of the preform 19 and the still-formable second fiberlayer 20 (see FIG. 2.9), which is impregnated with PU, and the shapingof the core layer 3 take place in a manner corresponding to the methodstep of the method described above that was explained with reference toFIG. 1.9.

A further method alternative will be described with reference to FIGS.3.1 to 3.9, method steps 3.1 to 3.4 corresponding to the method stepsdescribed with reference to FIGS. 1.1 to 1.4. These further methodalternatives provide that, when the molding tool 11 is open (FIG. 3.5),a spacer 21 is placed onto the preform 19 held on the mold base plate12. The mold counterplate 13 supported by the upper tool half isexchanged for the profiled mold counterplate 13′ (FIG. 3.6).

The second fiber layer 20 (FIG. 3.7, correspondingly FIG. 1.7), which isproduced outside the molding tool 11 and sprayed with PU resin, isintroduced into the open molding tool 11 (FIG. 3.8) and placed on thespacer 21, which is arranged on the preform 19. The edge portion of thepreform 19 is not covered by the spacer 21.

When the molding tool 11 is being closed (movement from FIG. 3.8 to FIG.3.8a ), the spacer 21 keeps the second fiber layer 20 at a distance fromthe preform 19, with the result that the second fiber layer 20 liesagainst the profiled mold counterplate 13′, which moves in the closingdirection. A spacing or a cavity in which the spacer 21 is arranged thusremains between the second fiber layer 20 and the preform 19.

During the last closing movement of the molding tool 11, the moldcounterplate 13′ and the mold base plate 12 press the edge portions ofthe second fiber layer 20 and of the preform 19 that lie on top of oneanother against one another. The foamable PU plastic is injected betweenthe hardened first support layer 4 of the preform 19 and thestill-formable second fiber layer 20, which is impregnated with PU, intothe spacing or cavity kept free by the spacer 21 (FIG. 3.9). Thepressure during the injection of the PU plastic and during the foamingof the PU foam presses the second fiber layer 20, which already liespartially or fully on the mold counterplate 13′, against the profiledmold surface of the second mold counterplate 13′, and shapes it thereonas the second profiled support layer 5. The PU foam forms the core layer3 of the composite component 1 and is completely enclosed by the twosupport layers 4 and 5.

The spacer 21 remains in the core layer 3 of the composite component 1.

While supplying heat, the composite component 1 is hardened in theclosed molding tool 11. The molding tool 11 is then opened and thecomposite component 1 formed is removed.

The mold base plate 12 as well as the mold counterplates 13 and 13′ maycomprise the negative-pressure device 15 described, such that the partslying thereon, like the cover layer 6, the preform 19 and the secondfiber layer 20, can be held by means of a negative pressure or vacuum asrequired during the individual method steps.

The spacer 21 is e.g. a self-inflatable film or a three-dimensionallydeformable mat structure.

When the molding tool is being closed, the self-inflatable film keepsthe second fiber layer 20 at a distance from the preform 19 andpreferably also in contact with the mold counterplate 13′. During theinjection of the PU plastic and the foaming of the PU foam, saidself-inflatable film is then punctured and remains in the core layer 3of the composite component 1.

The three-dimensionally deformable mat structure preferably consists ofplastics, such as e.g. polyester, with an open-pore structure.

List of reference signs 1 Vehicle composite component 2 Layer structure3 Core layer 4 First support layer 5 Second support layer 6 Cover layer7 Edge region 8 Flange 9 Edge portion 10 Edge portion 11 Molding tool 12Mold base plate 13 Mold counterplate 14 Mold cavity 15 Negative-pressuredevice 16 First fiber layer 17 Spray head 18 Heating device 19 Preform20 Second fiber layer 21 Spacer

1. A method for producing a vehicle composite component with a layerstructure having a core layer in a molding tool, the core layer beingformed with regions of different thickness, the method having the stepsof: placing a cover layer onto a mold base plate of the open moldingtool, introducing a first fiber layer, which is impregnated with PUresin and has not been subjected to forming, between the cover layer anda first mold counterplate of the open molding tool, closing the moldingtool and compression molding the first fiber layer, which is impregnatedwith PU resin, against the cover layer, as a result of which a preformwith a first support layer containing the first fiber layer is formedand hardened while supplying heat, opening the molding tool andreplacing the first mold counterplate with a second mold counterplatewith a highly structured mold surface, introducing a second fiber layer,which is impregnated with PU resin and has not been subjected toforming, between the preform arranged on the mold base plate and thesecond mold counterplate of the open molding tool, closing the moldingtool and injecting foamable PU between the first support layer of thepreform and the second fiber layer, the PU foam forming the core layerpressing the second fiber layer against the second mold counterplate,which has a profiled mold surface, and shaping it thereon as a secondprofiled support layer, opening the molding tool and removing thecomposite component formed.
 2. The method as claimed in claim 1, whereinthe first support layer and the second support layer are pressedtogether at the edge and adhesively bonded with PU and enclose the corelayer.
 3. The method as claimed in claim 1, wherein the first fiberlayer and/or the second fiber layer are/is impregnated outside themolding tool by spraying PU resin on one side or on both sides.
 4. Themethod of claim 1, wherein unordered or ordered fibers or at least onefiber mat form/forms the first fiber layer and/or the second fiberlayer, and wherein the fibers are in particular glass fibers.
 5. Themethod of claim 1, wherein, in step 1.5, firstly a spacer is applied tothe preform arranged on the mold base plate and then the second fiberlayer is introduced between the spacer and the second mold counterplateand wherein, in step 1.6, when the molding tool is being closed, thespacer keeps the second fiber layer at a distance from the preform andin contact with the second mold counterplate.
 6. The method as claimedin claim 5, wherein the spacer is a self-inflatable film or athree-dimensionally deformable mat structure.
 7. The method of claim 1,wherein the cover layer is a preformed cover layer.
 8. The method ofclaim 7, wherein the preformed cover layer forms an outer skin of thevehicle composite component